C language two-bit arrays and pointers

Question, what is the result of the following output, and what is the difference?

voidMain () {inta[3][4] = {1,2,3,4,5,6,7,8,9,Ten, One, A }; //output of3 addresses are the same, where is the difference? printf"\n%x", a); printf ("\n%x",*a); printf ("\n%x",&a);
System ("Pause");}

Wild yards like me are basically ignorant of this problem, so let's first understand it through a one-dimensional array.

voidMain () {intnum[5] = {1,2,3,4,5 }; printf ("\n%x", num);//initial address of first element, 1 int elements 4 bytesprintf"\n%x", &num);//an array of first addresses, an array of 5 elements, and 20 bytes. //printf ("\n%d", (* (&num)) [2]); you Know (* (&num)) is an array {1,2,3,4,5}-> &num is an address to the entire array//differenceprintf"\n%d",sizeof(*num));//4 *num Extract content by type address = 1, 4 bytesprintf"\n%d",sizeof(*&num));//*&num extract content by type addressGetChar ();}

By the above example, you can know

1. Num is the first address to the array, so the *num is the value of the first address of the array 1.

2. &num is the address that points to the entire array.

So let's look at an example of a two-dimensional array above.

1 voidMain ()2 {3     inta[3][4] = {1,2,3,4,5,6,7,8,9,Ten, One, A };4     5     //print out the entire array of elements and corresponding addresses6      for(inti =0; I <3; i++)7     {8          for(intj =0; J <4; J + +)9         {Tenprintf"%d,%x", * (* (a+i) +j), * (A + i) +j); One         } Aprintf"\ n"); -     } -  the     //3 results are the same, where is the difference?  -printf"\n%x", a);//A-line pointer -printf"\n%x", *a);//the value of the A-line pointer {1,2,3,4} -printf"\n%x", &a);//address of the entire two-dimensional array +      -printf"\n%d",sizeof(*a));//*a represents an array of a row {1,2,3,4}, +printf"\n%d",sizeof(**a));//4, there can be inferred that **a represents the first row array first address 1 Aprintf"\n%d",sizeof(*&a));//&a represents the first address of the entire two-dimensional array, then * (&a) takes the contents of the entire two-dimensional array, 12 elements, 48 bytes at  -  -System"Pause"); -}

　　

C language two-bit arrays and pointers